Not Safe at any Dose: Marijuana and Non-medical Use of Prescription Drugs

This is the second in a series of articles on how specific drugs affect the brain and body.

The brain drain
Myths that downplay the risks associated with drug use permeate youth culture and are embraced to rationalize experimentation with addictive drugs. Scientific evidence can help educators and parents de-bunk these dangerous myths.
Adolescents and young adults are the principal age groups using addictive drugs and are at the greatest risk for experiencing adverse consequences as a result of the early introduction of drugs into their brains. Early drug use can compromise academic achievement, school attendance, homework, participation in extracurricular activities, and school behavior. Drug use at a young age is also associated with addiction, violence, accidents, delinquency, criminal activity, and even death. As with any major public health problem, the inability to predict which young people will suffer detrimental, potentially life-threatening consequences from drug use is itself a reason to engage in widespread prevention efforts.
The brain has approximately one hundred billion nerve cells, with each cell producing 10,000 or more “wires” that connect with other cells. A critical component of brain development is accurate “wiring.” Imaging technologies that compare adolescent brains with those of adults have shown that the “wiring” of the adolescent brain is still immature, compared to the adult brain. Exposure to drugs before brain maturation may affect brain development, interfering with the wiring and circuitry of the brain in much the same way as a computer technician can damage a circuit board by zapping it with electrical jolts during the assembly process.
In the short term, a single dose of a drug can result in poor performance in a school or sports activity, accidents, violence, unplanned risky behavior, and the risk of overdosing. It can trigger repeated drug use, which is associated with serious health consequences, loss of desire to fulfill obligations, truancy, disorderly conduct, and social or family problems. Repeated drug use can also lead to addiction. Studies show that the earlier an adolescent begins using drugs, the more likely he or she will be to develop a substance abuse problem or become addicted to substances. Conversely, if an individual does not start using drugs during the teen years, he or she is less likely to initiate or develop a substance abuse problem later in life.
Statistics make a compelling case for focusing on preventing youth drug use. In 2006, among persons with substance dependence or abuse, the percentage dependent on or abusing illicit drugs was much higher in the 12-17 age group (57.4 percent) than among 18- to 25-year-olds (36.9 percent) or adults age 26 or older (24.1 percent), according to the 2007 National Survey on Drug Use and Health (NSDUH). One hundred eighty-one thousand youth (12-17 year-olds) received treatment for alcohol or illicit drugs (NSDUH 2007). Although prevention is a key to interrupting the progression to addiction, deterring marijuana use and prescription-drug misuse is particularly challenging because of the myths associated with these drugs.
Myth No. 1: Marijuana is a ‘soft’ drug
Marijuana use should not be considered a rite of passage. It is neither a “soft” drug nor a safe drug. The effects of marijuana can last up to 24 hours after administration, continuing to compromise reflexes, cognitive ability, and other brain functions. Driving while under the influence of marijuana is dangerous, as the use of this drug can impair motor function, concentration, and perception, thereby increasing the likelihood of road accidents. According to the 2006 Monitoring the Future study, the percentage of high school students who reported driving under the influence of marijuana (10.6 percent) was nearly as high as the percentage of those driving under the influence of alcohol (12.4 percent).
Accumulating evidence makes a forceful case for abstention from marijuana use. One study found that high school students who abstained from marijuana functioned better than occasional or frequent users during high school and during the transition to adulthood. During high school, abstainers fared better than experimenters and frequent users of marijuana on the basis of school engagement, deviant behavior, family and peer relations, and mental health. They were more likely to do homework and get better grades. When they turned 23, abstainers were twice as likely to graduate from college and much less likely to steal or to sell illicit drugs.
A long-term analysis of marijuana potency funded by the National Institute on Drug Abuse (NIDA) reveals that the strength of marijuana has increased substantially over the past two decades. Today, marijuana is more potent than ever before, and this elevated potency may be leading to an increase in teen marijuana treatment admissions and a rise in the number of marijuana-related emergency room episodes.

These worrisome results add to the growing body of evidence that the effects of youth marijuana use may endure into adulthood. Adolescents who used marijuana are twice as likely to use illicit drugs when they become young adults. In fact, in one study, individuals of twin pairs who used marijuana by age 17 had 2.1 to 5.2 times higher risk of other drug use (cocaine, heroin), alcohol dependence, and drug abuse/dependence than their co-twin who did not use before the age of 17.
Experiments with animals seem to corroborate these findings. Animals, which were not subject to environmental stressors, were exposed to the active ingredient of marijuana during adolescence. They were given a drug-free period and then, as adults, were given access to heroin. After maturation into adulthood, the early-exposed animals consumed higher amounts of heroin and showed greater heroin-seeking behavior than the non-exposed group. The effects of early exposure to marijuana were not restricted to behavior: components of the system in the brain that modulates pain and pleasure were changed in the animals’ adult brains, after exposure during adolescence.
Collectively, these findings suggest that marijuana, introduced during adolescence, may influence the biology of the brain, promote drug-seeking behavior, and affect social function during the transition to adulthood.
How addictive is marijuana, and how realistic is the perception that it is a “soft” drug? The 2007 NSDUH reported that in 2006, among adults aged 18 or older who first tried marijuana at age 14 or younger, 12.9 percent were classified with illicit drug dependence or abuse, a considerably higher number than the percentage (2.2 percent) who had first used marijuana at age 18 or older. Marijuana also ranked first as the most reported illicit drug resulting in abuse/dependence.
Early, frequent use of marijuana may be an independent risk factor for psychosis—even if use precedes the onset of schizophrenia or another form of psychosis. Marijuana may induce acute psychotic symptoms in vulnerable people and a persistent psychosis in some individuals who have not had prior signs of psychosis. Marijuana may also exacerbate psychosis in people with symptoms of schizophrenia, and these effects can persist after the drug is cleared from the body.
As with other addictive drugs, heavy marijuana use has many health and social consequences. Heavy marijuana use into adulthood creates an expanding set of health risks, including exercise-induced heart pain and reduced lung function, as well as objective and self-reports of adverse social consequences. During pregnancy, heavy marijuana use can lead to impaired fetal growth and development.
Myth No. 2: Prescription drugs used for psychoactive effects are safer than “street drugs”
Several classes of controlled prescription drugs—medications prescribed by doctors for legitimate medical purposes—have abuse and addiction potential. These include opioids prescribed for the management of pain, drugs to treat attentional problems and anxiety, and drugs to promote sleep. These drugs are safe and effective when used according to doctors’ prescriptions and advice. Abuse or non-medical use of prescription drugs is the use of drugs not prescribed for the individual, use of drugs solely for the experience or feelings they cause, or use of drugs for which the intended person has made false or inaccurate claims to obtain them.
A disturbing trend emerged last year, when NSDUH reported that first-time non-medical users of prescription drugs now equal first time users of marijuana and that misuse of prescription drugs among 12- and 13-year-olds exceeds marijuana use. The misuse of opioid pain killers is of particular concern because of the large number of users, the high addictive potential, and the potential to induce overdose or death.
Also of concern is that approximately 598,542 visits to emergency departments during 2005 involved the non-medical use of prescription drugs or over-the-counter medication or dietary supplements, with the majority involving multiple drugs (Drug Abuse Warning Network, 2005).
There are many factors contributing to the increased misuse of prescription drugs. There is a perception among young people that prescription drugs are safer than illicit street drugs. Moreover, many teens are not aware of the consequences of prescription drug misuse. Prescription drugs are also more easily attainable from friends and family.
There are indications that long-term misuse of pain medications can lead to addiction, and that intravenous use of this class of drugs places a person at increased risk of HIV and other infectious diseases. Additionally, because many of the prescription drugs that are abused share similarities with illicit drugs in the way they act on the brain, it is probable that some of the harmful consequences will be the same.
It is important for adults to recognize this growing problem and to help young people understand the risks of using prescription drugs non-medically. When used properly, under the supervision of a doctor, prescription drugs can be safe and effective. Used improperly, however, they can have serious consequences.
Preventing initiation and identifying problem use
Using marijuana or misusing prescription drugs in any amount is not safe. Scientists, educators, counselors, community coalitions, prevention experts, and others are working to expose dangerous drug myths and to increase awareness of the adverse physical, mental, emotional, and behavioral changes that can be associated with these substances. Testing students for drug use may help prevent initiation and identify drug users at an early stage, before a dependency sets in, thereby protecting adolescents and their fragile brains from the harmful effects of drug-using behavior.
A complete list of citations for this article is available at www.randomstudentdrugtesting.org